Local loop telecommunication repeater housings employing thermal collection, transfer and distribution via solid thermal conduction

ABSTRACT

An improved thermal design for passively cooled telecommunication repeater housings for use with wire transmission in the local loop outside plant is achieved by replacing the known convection based heat transfer designs with a design based on solid thermal conduction. A thermal chassis includes thermal collection, transfer and distribution members that collect the repeater modules&#39; waste heat through respective thermal interfaces, transfer the waste heat along respective thermal conduction paths to the environmental enclosure, and then distribute the waste heat over a substantial portion of the enclosure&#39;s available surface area to form an enlarged thermal interface for convectively transferring the waste heat to the ambient air. Heat transfer is further improved by expanding the enclosure&#39;s external surface area and fabricating the distribution members so that they are in permanent and intimate thermal contact with the enclosure&#39;s expanded surface area.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] This invention relates to passively cooled repeater housings foruse in a telecommunication network's wire transmission local loopoutside plant and more specifically to repeater housings having improvedthermal transfer characteristics, improved performance under solar loadsand direct access to repeaters and voltage surge protectors.

[0003] 2. Description of the Related Art

[0004] In the telecommunications industry, voice, data and videotransmission signals are transmitted over wire, fiber optic and wirelessnetworks. Although the fiber optic and wireless networks were designedto meet the current demand for high speed signal transmission, themassive investment in the wire network, or the “copper plant” as it iscommonly referred to, necessitates its continued use. The cost and timeinvolved to completely replace the millions, if not billions, of milesof copper (or aluminum) wires in the United States alone with fiberoptic lines and wireless networks is prohibitive. Although originallydesigned to carry only voice grade signals, the continued development ofincreasingly sophisticated digital signal processing (DSP) techniquessuch as T-carrier, ISDN, Direct Digital Service (DDS) and most recently,High bit-rate Digital Subscriber Line (HDSL) allow thetelecommunications industry to transmit rapidly growing volumes of highspeed signals over the copper plant in a more cost effective manner thanconversion to the newer transmission technologies in all but the highvolume networks.

[0005] As shown in FIG. 1, a typical telecom network 10 includes anumber of central offices 12 that transmit a massive amount of very highspeed signals between offices over inter-office trunks 14 and a numberof local loops 16 that distribute portions of the signals from a centraloffice 12 to a customer premises 18 and between customer premises 18. Aclear distinction has existed between the offices' inter-office trunks14 and the local loops 16. First, each central office will typicallyservice many user premises. As a result, the cost of replacing thecopper plant for the central offices' inter-office trunks is much lowerthan replacing it for all the individual users. Second, the signaltraffic between central offices is typically much higher volume and muchhigher speed than is required in the local loop.

[0006] As a result, inter-office trunks 14 have been largely convertedfrom copper wire to the more sophisticated fiber optics, microwavetransmission and even satellite transmission systems while the localloops have used the updated DSP technologies in conjunction with theexisting and even new installation copper 20. However, for the lastseveral years, the explosive growth in demand for high speedtelecommunications services such as those required for businessnetworking and the Internet has been stressing the capabilities of thecopper network in the local loop.

[0007] One particular area in which the copper network is being stressedoccurs in the “outside plant”, i.e. that part of the local loop thatlies outside the controlled environments of telecom or user buildings,generally regarded as the lowest technology link in the network andsymbolized by the lineman on a pole or in a manhole.

[0008] As signals are transmitted over the copper wires in the outsideplant they degrade and lose signal integrity. As a result, the industryhas developed circuits called “mid-span repeaters” or simply “repeaters”that regenerate a degraded signal. Depending upon the transmissiontechnology used, the repeaters are placed every three to twelve thousandfeet along the transmission path.

[0009] Repeaters are manufactured by numerous suppliers to support avariety of copper transmission technologies. Several industry standardconnector and case standards are followed to allow repeaters fromdifferent suppliers and of different technologies to be interchanged.FIGS. 2a and 2 b illustrate a standard 239 mini-repeater 22 often usedwith older T-1 technology and a standard 239 double-wide repeater 24that is commonly used with the ISDN, DDS and HDSL technologies. The T-1239 mini-repeater generates approximately 0.75 watts of waste heatwhereas an HDSL 239 double-wide, while only twice as big, generates upto 6 watts of waste heat. Because of the nearly order of magnitudeincrease in power consumption, the 239 doublewide is frequently providedwith slits that facilitate air flow over the hot parts to convectivelyremove heat. The power consumption of ISDN and DDS repeaters is alsosubstantially greater than T-1 239 mini-repeaters, but less than that ofthe more sophisticated HDSL repeaters.

[0010] Because mid-span repeaters are used in the outside plant,frequently in manholes 28, they must be placed in a repeater housing 26such as the AT&T '809 Apparatus Case 30 shown in FIGS. 3a and 3 b, theSPC Series 7000 Enclosure 32 shown in FIGS. 3c and 3 d, or the genericcabinet style enclosure 34 shown in FIG. 3e. The primary function ofthese known repeater housings is to provide an environmental enclosurethat shields the repeaters from the elements; wind, rain, dust, solarenergy, animals, vandals etc. They are oftentimes formed from strongcorrosion resistant materials such as stainless steel or hard plasticand are hermetically sealed, often under a positive pressure. In mildenvironments the repeater housing do not have be corrosion resistant andabove ground cases are often vented.

[0011] The housings must accommodate standard sized repeater modulesthat are built by a number of vendors. The housings must also providephysical access to repeater modules and voltage surge protectors so thatthey can be removed and replaced in the field in a “plug-in” mannerwithout having to disassemble the module or disturb the operation ofother repeaters. Furthermore, to improve reliability and avoid theexpense of requiring electrical power at each repeater site, the housingmust be passively cooled to remove the waste heat generated by therepeaters. It is well understood in the telecommunications industry thatthermal stress can cause short term failures, intermittent operationdeviations and significantly shorten the life of electronic equipment.Most telecom electronics is installed in buildings that provide acontrolled and relatively benign thermal environment. In contrast,repeaters deployed in the outside plant must work in the harsh, naturalenvironment.

[0012] The AT&T '809 apparatus case 30 shown in detail in FIG. 4 and thedouble size '819 apparatus case described in AT&T Practice 640-525-307Issue 5, April 1986 is a molded plastic rectangular housing that islightweight, does not corrode, and optimizes the use of available space.The '819 obsoleted AT&T's earlier '479 apparatus case described in AT&TPractice 640-527-107 Issue 3, March 1986 that had the same general shapebut was constructed from cast iron, and thus extremely heavy and subjectto corrosion.

[0013] The '809 includes a molded base 36 for receiving a stub cable 38from a splice case in the local loop and a mounting bracket 40 formounting the case on the wall of a manhole, for example. Pressure andpressure relief valves are also provided in the base. Stub cable 38 issplit into individual wires that are run through base 36 andwire-wrapped to the backside of repeater/protector connectors 42, whichhave a female PCB edge connector 44 for mounting the repeater module andmultiple sockets 46 for mounting gas tube style voltage surge protectors48.

[0014] A molded housing 50 having an array of plastic stubs 52 is boltedon base 36 so that stubs 52 define slots 54 over the respectiverepeater/protector connectors 42 for separating and supporting therepeater modules. A molded cover 56 is then bolted on top of housing 50.The cover can be removed to gain direct access to the top of theenclosed repeater modules for easy installation and replacement. Theillustrated '809 case is designed, physically and electrically, to hold12 239 mini-repeater modules 22 or 6 non-standard repeater modules 25with 2 slots used for support functions. The '809 case was designed forthe 239 mini-repeater and thus does not physically accommodate thestandard 239 double-wide case. Some suppliers have developed a variationof the 239 double-wide that is even wider and has slots 58 in the caseto allow it to fit into two slots in the '809 and '819.

[0015] To make the best use of the space available inside housing 50,voltage surge protectors 48 are positioned in connector socketsunderneath the repeater modules. To gain access to the protectors, alineman must first remove the repeater module, taking it out of servicetemporarily. Because the voltage surge protectors are positioned at thebottom of narrow slots 54 they can be very difficult to remove.Consequently, AT&T provides a special 829A tool and a detailedmulti-step process for extracting the gas protectors. In practice,lineman sometimes use a long screwdriver to pop the protectors loose.However, with +/−130 volts active on the contacts of the protectorsockets, attempted service without the proper tool can be hazardous,both to the lineman and to the equipment.

[0016] Although the practice makes no mention of thermal considerations,the '809 relies on convection and, to a lesser degree, radiation toremove waste heat from the repeater modules. The repeater module and, inthe case of the slit, modified double-wide, the components themselvesheat the air which transfers some heat to the adjacent walls of the caseand rises to convectively transfer the rest of the heat to the top ofthe case. The walls and end of the case absorb the waste heat and thenconvectively transfer it to the surrounding environment. Notice, stubs52 position, but do not tightly enclose the repeater modules toencourage air flow to improve convective heat transfer to the top of thecase.

[0017] The SPC 7000 Series enclosure 32 shown in FIGS. 5 and 6 is athin-walled stainless steel cylindrical enclosure. The 7000 Seriesenclosure includes a cylindrical base 60 into which it receives a stubcable 62. A lightweight thin aluminum basket 64 is centrally mounted ona bracket 66 in base 60. A number of female PCB repeater connectors 68are mounted in slots in the bottom of the basket with their pins 70 wirewrapped (not shown) to the stub cable. A voltage surge protectorassembly 72 is then mounted on the back side of connector 68 andrepeater modules 24 are mounted on the top side in the basket. Bracket66 allows basket 64 to be tipped to access the backside wiring.Alternately, the basket can be replaced with a chassis in which themodules are inserted horizontally from one side and access to theprotectors is gained from the other side. A dome 74 fits over base 60and is hermetically sealed using a V-groove clamp 76, an O-ring 78 a andan O-ring retainer 78 b. Similar to the '819, the Series 7000 enclosurerelies on radiation and convection to move the waste heat generated bythe repeater modules to the dome and then to the surroundingenvironment. To this end, the 239 double-wide repeater modules and thebasket are formed with slits to encourage air flow. In its normalupright position, the heated air rises to the top of the dome where itis then convectively transferred to the environment.

[0018] Access to the repeater is gained by removing the entirecylindrical dome. The removal of the entire cylindrical dome of an SPC7000 style repeater housing is of little consequence in above ground andlow density below ground (manhole) installations, however, with sharplyincreased crowding in below ground facilities, the extra clearancerequired to remove the entire dome has become a drawback to theotherwise satisfactory cylindrical dome repeater housing configuration.In response, repeater housing mounting brackets have been developed thatallow the entire housing to pivot away from the mounting surfacesufficiently to permit the cylindrical dome to be removed withoutrequiring excessive vertical clearance directly above its installation.

[0019] While such access to the modules and voltage protectors may seemconvenient, in the reality of a crowded manhole, “tilt, swivel andaround the back” represent difficult access, excessive installation andservice time and risk to the hundreds of wires connected to the repeatermodules. Furthermore, the +/−130 VDC span power is not deactivatedduring service of the repeater housing, therefore, installation andremoval of the voltage protector assemblies connected to this voltagemust be performed with serious caution.

[0020] The '819 apparatus case and Series 7000 enclosure, and thethermal transfer techniques they embody, are designed to handle up to 25239 mini-repeaters and do so with no problem. However, those samehousings are limited to 2 or maybe 3 HDSL repeaters before their thermaltransfer capabilities are overloaded. With the demand for high bandwidthservice continuing to grow and the amount of available space eitherbelow ground in manholes or above ground reaching or exceeding capacity,repeater housings in which a majority of the slots must remain empty forthermal reasons is clearly a problem. Furthermore, direct, easy and safeaccess to the repeater modules and their voltage surge protectors is animportant consideration.

SUMMARY OF THE INVENTION

[0021] In view of the above problems, the present invention provides animproved thermal design based upon solid thermal conduction forpassively cooled repeater housings used in a telecommunication network'swire transmission local loop outside plant.

[0022] This is accomplished by using thermal collection, transfer anddistribution members to collect the repeater modules' waste heat throughrespective thermal interfaces, transfer the waste heat along respectivethermal conduction paths to the environmental enclosure, and thendistribute the waste heat over a substantial portion of the enclosure'savailable surface area to form an enlarged thermal interface forconvectively transferring the waste heat to the ambient air. In acurrently preferred approach, the collection, transfer and distributionfunctions are integrated in a thermal sleeve that minimizes the thermalresistance between the module and the enclosure. To further improve heattransfer, the distribution member and enclosure are preferably formed todistribute the waste heat over an expanded external surface area. Thisis accomplished by designing the repeater and voltage protectorassemblies so that they can be removed via top/front access, preferablyindependently of each other. This allows the distribution members to befabricated in permanent and intimate thermal contact with the enclosureby, for example, compression fitting complementary corrugation pieces ormolding one inside the other.

[0023] These and other features and advantages of the invention will beapparent to those skilled in the art from the following detaileddescription of preferred embodiments, taken together with theaccompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1, as described above, is a simplified illustration of atelecommunications network;

[0025]FIGS. 2a and 2 b, as described above, depict a standard 239-minirepeater and a standard 239 double-wide repeater case, respectively;

[0026]FIGS. 3a through 3 e, as described above, depict a variety ofknown repeater housings;

[0027]FIG. 4, as described above, is a perspective and partiallycut-away view of an AT&T '809 apparatus case;

[0028]FIG. 5, as described above, is an exploded view of an SPC 7000series repeater housing;

[0029]FIG. 6, as described above, is a tipped view of the SPC 7000series repeater housing;

[0030]FIG. 7 is a thermal resistance model of a repeater housing;

[0031]FIGS. 8a through 8 e are simplified illustrations of thermalcollection, transfer and distribution mechanisms in a thin-walledenvironmental enclosure in accordance with the present invention;

[0032]FIG. 9 is a simplified thermal resistance model of a repeaterhousing incorporating the thermal collection, transfer and distributionmechanisms;

[0033]FIG. 10 illustrates a preferred thermal sleeve for performing thethermal collection, transfer and distribution;

[0034]FIGS. 11a through 11 d illustrate different embodiments of avoltage surge protector assembly for the repeater that facilitate directaccess within the repeater housing;

[0035]FIG. 12 is a perspective and partially enlarged view of a repeaterhousing that uses the thermal sleeve within a modified SPC 7000 seriesthin-walled environmental enclosure;

[0036]FIG. 13 is an exploded view of the thermal sleeve and the actuatormechanism for urging the sleeve against the interior wall of theenvironmental enclosure of the repeater housing shown in FIG. 12;

[0037]FIG. 14 is a plan view of the repeater housing shown in FIG. 12 inits expanded and retracted positions;

[0038]FIGS. 15a and 15 b are views along section line 15-15 in FIG. 14of the repeater housing in its expanded and retracted positions,respectively;

[0039]FIG. 16 is a tipped view of the repeater housing shown in FIG. 12;

[0040]FIG. 17 is a perspective and partially enlarged view of a solarshield for the repeater housing shown in FIG. 12;

[0041]FIGS. 18a, 18 b and 18 c are respectively detailed implementationsof the fins shown in FIG. 17;

[0042]FIG. 19 is an exploded view of a preferred aboveground cylindricalrepeater housing;

[0043]FIG. 20 is a partially cut-away view of the assembled cylindricalrepeater housing shown in FIG. 19;

[0044]FIG. 21 is an exploded view of a preferred below-groundcylindrical repeater housing;

[0045]FIGS. 22a and 22 b are respectively plan views of the below-groundrepeater housing without its cover and the bottom side of the cover;

[0046]FIGS. 23a and 23 b are partial sectional views showing thebelow-ground cylindrical repeater housing in its uncovered and coveredconfigurations, respectively; and

[0047]FIG. 24 is an exploded view of a threaded fin below-groundcylindrical repeater housing.

DETAILED DESCRIPTION OF THE INVENTION

[0048] The present invention applies thermal modeling and designprinciples to first identify and then solve the thermal transferproblems in known local loop repeater housings. As the very simplifiedthermal model 100 for the known repeater housings shown in FIG. 7illustrates, waste heat generated by the aggregation of “HOT PARTS” inthe repeater modules flows to the cooler AMBIENT AIR. With the repeatersoperating, the temperature of the heat generating parts (HOT PARTS) andall other thermal nodes between the HOT PARTS and the AMBIENT AIRsurrounding the repeater housing will increase until thermal equilibriumis reached, i.e. the quantity of heat flowing out of the repeaterhousing equals the quantity of waste heat generated within. The thermalresistances represent the main heat transfer paths associated with solidand gaseous conduction, natural convection and radiation, and take intoconsideration the thermal properties of thin materials and poorly matedsurfaces. In contrast to simple electrical networks with similarschematic appearance, most thermal resistances vary non-linearly withthe temperature across and the heat flow through them. Accordingly, aprecise analysis of this heat flow system would involve sophisticatedtechniques such as Finite Element Analysis and/or Computation FluidDynamics to solve the array of partial differential equations.

[0049] Heat generated in the aggregation of HOT PARTS can flow outwardalong three main paths. The primary path Θ_(H-E) relies upon naturalconvection to circulate air through the holes in the repeater modulesand carry the heat to the inner surface of the ENCLOSURE at its highestpoint. Another convective path Θ_(H-C) transfers a portion of the wasteheat to the CHASSIS (the Series 7000 basket and '819 stubs). The lastmajor path Θ_(H-C) uses a combination, which depends upon the specificpackaging of the repeater, of solid and gaseous conduction, naturalconvection and radiation to transfer waste heat to the MODULE casing.

[0050] Heat transferred to the repeater MODULE casing can flow outwardalong two main paths. A first path Θ_(M-E) to the inner surface of theENCLOSURE is almost entirely via natural convection and is verydependent upon the design of the CHASSIS. The small space generallyprovided between MODULE and CHASSIS can severely restrict naturalconvection air flow over the sides of the MODULE because of boundarylayer effects. The other path Θ_(M-C) to the CHASSIS uses convection,gaseous conduction and radiation, and is also very dependent upon theCHASSIS design. The contribution of solid conduction is minimal becausethe mating surfaces are not sufficiently conforming and under enoughcontact pressure to exclude the air interface. Furthermore, theprofusion of holes in both the repeater MODULE and in the CHASSISsignificantly reduce the surface area available for MODULE to CHASSIScontact.

[0051] The path Θ_(C-E) from the CHASSIS to the ENCLOSURE includesnatural convection, which concentrates the transferred heat on the innertop surface of the ENCLOSURE, radiation, which transfers a smallfraction of the waste heat to the side walls, and solid conduction tothe bottom of the ENCLOSURE. The thin metal or plastic CHASSIS and thefrequent presence of thermal barriers in the form of mechanical jointsgenerally minimize heat transfer along the solid conduction path.

[0052] The final path Θ_(E-A) is from the inner surface of the ENCLOSUREto the surrounding AMBIENT AIR where the waste heat is dissipated. Thatpart of the path from the inner surface to the outer surface of theENCLOSURE is via solid conduction. Because the inner to outer distanceis small and the transfer area large, the solid conduction resistancethrough to the outside of the ENCLOSURE is negligible. However, even ifthe environmental ENCLOSURE is metallic as in the stainless steel SPC7000, the thermal resistance representing the diffusion of waste heatacross the surface area of the thin metal or most plastic ENCLOSURES isvery high and thus the heat transferred to an area on the ENCLOSUREremains localized. From the heated surface of the ENCLOSURE, the wasteheat is then transferred via natural convection to the surroundingAMBIENT AIR.

[0053] This model shows that known repeater housings 1) primarily usehigh thermal resistance, natural convection within the housing totransfer waste heat to the environmental enclosure and 2) makeinefficient use of the surface area of the enclosure as a thermalinterface to the surrounding ambient air. As a result the capacity ofthe known repeater housings to dissipate heat and thus the number ofHDSL and other high or medium power consumption repeaters (such as ISDNand DDS) that can be deployed within known housings is severelyconstrained. To solve this problem, Applicant applies the principles ofthermal collection, transfer, and distribution via solid thermalconduction as illustrated in FIGS. 8a through 8 e to reduce the thermalresistance between the HOT PARTS and the AMBIENT AIR with the resultbeing a dramatic increase in the thermal transfer capacity of therepeater housing.

[0054] Thermal collection members 102 shown in FIG. 8a and 104 shown inFIGS. 8b-8 e, which are manufactured from a thermally conductivematerial such as aluminum or thermally conductive plastic, form athermal interface 106 with repeater module 108 that collects the wasteheat generated within the repeater module and reduces the thermalresistance Θ_(H-M) from the HOT PARTS to the repeater MODULE. Inaddition, the collection member may perform, in full or in part, themechanical functions performed by the chassis in known repeaterhousings.

[0055] Taking into account only the thermal and mechanical functions,thermal collection member 104 is preferred over member 102 because itfully surrounds the repeater module and thus collects waste heat fromeach of its major surfaces. However, space and weight considerations,lower waste heat transfer requirements or the fact that a particularmodule generates a vast majority of its waste heat on a single surfacemay favor collection member 104. In either case, it would be ideal ifthe collection member's inner surface 110 and the repeater module'souter surface 112 were in intimate mechanical contact over the fullsurface of the repeater module. This would “short out” thermalresistance Θ_(M-C) from the MODULE to the CHASSIS. However, mechanicaltolerances and small variations in the actual outer dimensions ofrepeater modules from different manufacturers make full intimatemechanical contact difficult and not cost effective to achieve. However,the actual benefits from full contact in contrast to small airinterfaces are small.

[0056] For example, as in FIG. 8c, if a uniform air gap of 0.020 inches(enlarged for clarity) was maintained between the collection member andthe repeater module, the thermal resistance Θ_(M-C) from the MODULE tothe CHASSIS would be approximately 0.68° C. per watt for a 239 doublewide module. For an HDSL repeater generating 6 watts of waste heat, ifall that heat was transferred across air interface 114, the differentialtemperature across the interface would only be approximately 4.1° C., anacceptable fraction of the overall thermal transfer budget and a majorimprovement over the prior art. If an unacceptably large air gap wereencountered, a conductive shim 116 as illustrated in FIG. 8 c could beused to replace some of the air in the thermal interface.

[0057] The collection member also functions to reduce thermal resistanceΘ_(H-M) from the HOT PARTS to the repeater MODULE casing. Repeatermodule casings are generally made from thin plastic or metal and thusexhibit a relatively high thermal resistance to heat diffusion over thesurface of the casing. As a result, a hot part will tend to produce ahot spot on the adjacent module casing that will elevate the temperatureof the hot part even if the average temperature of the module issubstantially lower. The thermally conductive collection member acts inparallel with the module casing's relatively high thermal diffusionresistance to bleed off waste heat from potential hot spots.

[0058] A thermal transfer member 118, manufactured from a thermallyconductive material such as aluminum or thermally conductive plastic,provides a conduction path that is designed to “short out” thermalresistance Θ_(C-E) from the CHASSIS to the inside of the ENCLOSURE bychanging it from a natural convection and radiation path to one usingsolid conduction. Analysis and tests demonstrate that use of a transfermember 0.2 inches thick, 2 inches long and 6 inches high produces athermal resistance Θ_(C-E) of approximately 0.42° C. per watt. For anHDSL repeater generating 6 watts of waste heat, if all that heat wastransferred along transfer member 118, the differential temperaturewould only be about 2.5° C., a major improvement over the thermalresistance that can be achieved with natural convection and radiation.The thermal resistance Θ_(C-E) can be further reduced and thetemperature difference across the transfer member made to approach zeroby moving the repeater closer to the side of the enclosure.

[0059] Oftentimes the transfer of waste heat to the enclosure requirestransferring waste heat across mechanical joints. The thermal resistancecaused by such mechanical joints is reduced by minimizing the thicknessof the air film sandwiched in the joint and increasing the thermalinterface area. The overlapping and interdigitated joints 120 and 122shown in FIGS. 8b and 8 c, respectively, solve the problem, and areparticularly useful in transferring waste heat to the housing's top andbottom surfaces.

[0060] Distribution addresses Θ_(E-A), the path from the ENCLOSURE tothe surrounding AMBIENT AIR. The largest fraction of Θ_(E-A) isdetermined by the exposed surface area of the enclosure that carriessignificant amounts of waste heat. The larger the surface area the lowerthe resistance. In known convection based repeater housings, adisproportionate share of the waste heat is distributed to the topsurface of the enclosure, which represents only a small fraction of theavailable surface area. Furthermore, the top surface is typically ahorizontal surface, which is less effective for natural convection thanvertical surfaces of equal size. Third, the thin stainless steel orplastic enclosures are extremely poor at diffusing heat over theirsurfaces and thus tend to localize the waste heat. Lastly, the availableexternal surface area is limited by the smooth shape of the enclosure.Taken together, these limitations provide an insufficient effectivesurface area for efficiently transferring waste heat to the AMBIENT AIR.

[0061] The distribution members shown in FIGS. 8a-8 e overcome each ofthese limitations and realize a substantial reduction in thermalresistance Θ_(E-A) by increasing the total surface area that carriessignificant amounts of waste heat. Waste heat is primarily distributedover the sidewalls of the enclosure, which typically have a much largersurface area than the top and are usually oriented in a verticaldirection. Secondarily, waste heat can also be distributed to the baseand top cover. Most importantly, the distribution member creates athermal interface that directly distributes the waste heat over theenclosure's surface area rather than relying on the enclosure itself todistribute heat. Lastly, the enclosure's external surface area can beexpanded by a factor of 200% to 400% or even more.

[0062] As illustrated in FIG. 8a, a distribution member 124,manufactured from a thermally conductive material such as aluminum orthermally conductive plastic, is placed in close, conformal thermalproximity to the inner wall 126 of the environmental enclosure 128.Although distribution elements of the invention can and will be used toenhance thermal transfer from many different surfaces of various typesof repeater housings, in the example of the SPC 7000 series, an aluminumdistribution element averaging 0.15 thick, can turn the vertical sidesof the environmental enclosure dome into a very effective thermalinterface to the surrounding ambient air and substantially reducethermal resistance Θ_(E-A) This simple distribution member creates athermal interface 129 between the distribution member and the enclosurethat directly distributes waste heat over an enlarged vertical surfacearea.

[0063] As illustrated in FIGS. 8b-8 e, the available external surfacearea can be greatly expanded with supporting distribution. Merelyexpanding the external surface area without supporting distribution isof limited value. As shown in FIG. 8b, the environmental enclosure,which is generally smooth sided in known repeater housings, can becorrugated 130 to increase its surface area by a factor of 200% to 400%.Because thin material environmental enclosures are poor heatdistributors, distribution member 124 is shaped to contact flanks 132 ofcorrugations 130. As a further refinement, distribution member 124 isformed with at least one bifurcated distribution fin 134. Thisbifurcated design saves weight and provides some slight flexibility toconform to and apply pressure to flanks 132 of corrugations 130. Forsimilar reasons, it is recommended that unsupported space be left in theouter diameter 136 and inner diameter 138 of corrugations 130. Inaddition to accommodating manufacturing tolerances, this flexible findesign can also provide some cushioning to shocks from both handling andvandalism. In a variation of this design, the environmental enclosuremight be formed from molded plastic or fiberglass over a solid thermallyconducting inner structure (not shown).

[0064] As shown in FIG. 8c, an alternate approach uses a corrugatedenvironmental shell 140 which is lined with a thermally conductingmaterial 142 to provide thermal distribution. Thermal lining 142 isjoined to the inner distribution element 124 in a thermally conductivejoint 144 using dip braising, thermally conductive adhesives, etc. Thisapproach allows very effective distribution to be accomplished atminimum weight.

[0065] Yet another alternative is illustrated in FIG. 8d, in which fins146, formed from a suitable thermally conducting material such asaluminum, are placed on the exterior of the environmental enclosure 128.With this alternative, the primary distribution member 148 is placed onthe outside of environmental enclosure 128 and a overlapping thermaljoint 130 is used to make the thermal connection from transfer member118 to distribution member 148. So long as care is taken to create agood thermal joint at the transfer to distribution interfaces, there islittle thermal detriment to locating some or all of the distributionelement on the exterior of the environmental enclosure. Because thisalternative places thermally conductive material on the outside of theenvironmental enclosure, it would only be suitable in non-corrosiveenvironments or if implemented with corrosion resistant material.

[0066] The above expanded external surface alternatives are meant toillustrate methods to maximize distribution. Many repeater housings willnot require maximum distribution. For example, FIG. 8e illustrates arelatively simple way to expand the external surface area of theenvironmental enclosure. Short fins 150 can be fastened to theenvironmental enclosure 128 by a process such as spot welding. Althoughthe poor thermal conductivity of stainless steel and the thermalresistance of the enclosure-to-fin interface 152 will limit theefficiency of such a design and will limit the useful height of thefins, it is practical to double the effective external surface area of aselected zone on a repeater housing in this manner.

[0067] By employing the collection, transfer, and distributionprinciples via solid thermal conduction, the convection based modelshown in FIG. 7 can be further simplified to a conduction based model154 as shown in FIG. 9. The thermal resistance from the HOT PARTS to theMODULE Θ_(H-M) is primarily set by the repeater's design, however, asdiscussed previously, the collection member reduces this resistancesomewhat by diffusing module casing hot spots. The thermal resistanceΘ_(M-E) from the MODULE to the inside surface of the environmentalENCLOSURE is so significantly reduced that the parallel convective pathscan be eliminated from the model. They still remain and a prudentdesigner will seek to minimize them, however the effect is at mostsecond order. Tests have shown that Θ_(M-E) can be reduced toapproximately 1° C. per watt for a 239 double wide module, resulting inthe transfer of up to 6 watts of heat from an HDSL repeater with atemperature differential of only 6° C. The thermal resistance Θ_(E-A)from the ENCLOSURE to AMBIENT AIR has also been significantly reduced bycombining the distribution techniques with an expanded external surfacearea. The bottom line is that repeater housings that could accommodate 2or maybe 3 239 double wide modules can now accept 8-12 modules.Furthermore, these principles can be used to design repeater housingsthat satisfy both the environmental and thermal demands.

[0068] To illustrate the collection, transfer and distribution functionsand how they simplify and greatly reduce the thermal resistance, eachfunction was depicted in FIGS. 8a-8 e as a separate physical element.While appropriate in some applications, the separation of elements isnot always necessary of even desirable. As shown in FIG. 10, the threefunctions can be integrated into a thermal sleeve 170 formed from asingle piece of aluminum extrusion. This specific sleeve was designedfor use in the repeater housing detailed in FIGS. 12-16, and thusincludes shoulder screws 240 and an inner T-slot 268 a for mounting thethermal sleeve.

[0069] Thermal sleeve 170 has an inner dimension 172 that forms athermal interface around repeater module 108 for collecting waste heat.The sleeve is moved from the center of the repeater housing to the sidewall of the environmental enclosure to shorten the thermal transfer pathto the thickness of the sleeve's front surface 174. That same frontsurface defines a distribution member 176 that is formed in intimatecomplementary thermal contact with the enclosure side wall's interiorsurface. In this case, the distribution member has an arcuate shape thatmatches that of a cylindrical environmental enclosure. The thermalsleeve is a very efficient, low thermal resistance design thateffectively “shorts out” thermal resistance Θ_(M-E) from the MODULE tothe ENCLOSURE and substantially reduces thermal resistance Θ_(E-A) fromthe ENCLOSURE to the AMBIENT AIR. Furthermore, the thermal sleeve isrelatively light weight, compact and provides the mechanical supportfunctions for the repeater module.

[0070] As will be described in great detail in FIGS. 12-16, the SPC 7000Series enclosure can be modified to incorporate the collection, transferand distribution elements of the invention using a plurality of thethermal sleeves shown in FIG. 10. The modified enclosure still requiresthe lineman to remove the entire dome to access the repeater modules andthen tip the thermal core to access the voltage surge protectors. Inaddition to the awkwardness of this process, it requires that the domeand the distribution members be separable, which is sub-optimal from athermal transfer perspective.

[0071] As will be illustrated in detail in FIGS. 19-24, the preferredapproach is to manufacture the repeater housing so that theenvironmental enclosure and thermal transfer chassis are non-separableby, for example, compression fitting or molding the two parts together.To provide access to the repeater modules, a seam is provided at the topof the enclosure so that a cover can be removed, without disturbing thethermal transfer path from the thermal chassis to the enclosure'ssidewalls, to provide top/front access to the repeater modules. Inaddition, the voltage surge protector assemblies are redesigned as shownin FIGS. 11a-11 d so that the voltage surge protectors can be accessedthrough the top, either independently of the repeater module or afterfirst removing the module.

[0072] A preferred embodiment of protector assembly 180 is illustratedin FIG. 11a, in which the female pin portion 182 of a protectorconnector is installed on a printed circuit board 184 adjacent to arepeater connector 186. Although shown separately, these two connectorsmay be merged into a single custom connector. The individual protectorelements 188 are mounted on a specially designed printed circuit board190 with the male pin portion 192 of the protector connector.Alternately, the connector's male pins can be attached directly to theprotector elements thereby eliminating PCB 190. The resulting protectorassembly 190 is preferably made as tall or taller than the adjacentrepeater 108 with a slot 194 to facilitate easy access without having toremove the repeater module or risk contacting the high voltage presenton the repeater and protector connectors.

[0073] Because of the large and rapidly rising currents produced bylighting or utility power cross induced voltage surges, the method usedto connect elements 188 to the repeater housing wiring is critical.First, the telecom wires should be routed to the female protectorconnector 182, not to repeater connector 186. Second, the protectorconnector must be designed with sufficient spacing between individualcontacts to resist high voltage breakdown and utilize contact elementscapable of carrying the high currents expected. Third, theinterconnection between the male protector connector 192 and theindividual protector elements 188 must be capable of carrying these highcurrents and have a low inductance that passes the rapidly risingcurrent waveform with minimum impedance. A multi-layer printed circuitboard with heavy and wide copper traces, designed with very high speedcircuit layout practices, can meet these requirements.

[0074] Another advantage of this type of protector assembly is that itcan easily accommodate test jacks 196 and/or indicator lights 198, asillustrated in FIG. 11b, that are able to take advantage of electricalaccess to the repeater wiring and combine it with direct top/frontaccess. If desired, the individual protector elements can either bepermanently connected to PCB 190 or can be installed in sockets to allowindividual service. As illustrated in figure 11c, the assembly can alsoaccommodate non-cylindrical protector elements 200 such as solid statevoltage surge protectors.

[0075] An alternative protector assembly 202 is illustrated in FIG. 11d,in which protector access without repeater removal is sacrificed for asmaller footprint. The female repeater connector 204 is elevated so thatthe female protector connector 206 is installed under the repeatermodule. The protector elements are mounted on a PCB with an edgeconnector 208 that is inserted into connector 206. PCB edge connector208 is used for illustration only in that a connector style with highercurrent ratings might be required for this application. This alternateembodiment still provides direct access to the protectors from the topor front of the repeater housing, safe access without the use of specialtools and the ability to accommodate a wide range of protector elements.

[0076] The repeater housing 210 illustrated in FIGS. 12-16 is a modifiedSPC Series 7000 repeater housing that incorporates the collection,transfer and distribution techniques described in FIGS. 8-10 above withthe existing thin-walled stainless steel environmental enclosure. Byusing the existing Series 7000 to provide the environmental enclosurewiring, connectors, telecom accessories, pressurization and ventfittings, sealed mechanical joints, deep drawn, stainless steel thinwall environmental enclosures, etc. necessary to a repeater housing,Applicant avoided the need to develop, test and gain telecommunicationsindustry approval for these elements, which are necessary in a repeaterhousing, but incidental to the thermal problem.

[0077] As shown in FIGS. 15a-b, the environmental enclosure of housing210 includes a base 212 and a dome 214 that are fabricated as seamlessthin, approximately 0.035 inch thick, deep drawn stainless steelcylinders having flanges 216 and 218 formed at their respective openends. An O-ring 220 is positioned on flange 218 and secured in positionby O-ring support 222. When dome 214 is installed, the inside wall ofthe dome fits snugly over O-ring support 222 with its flange 216 restingon O-ring 220. A V-groove clamp 224 is drawn tight over the O-ringassembly to mechanically fasten base 212 and dome 214 together and sealtheir joint.

[0078] A stainless steel mounting bracket 226 is fastened to the bottomof base 212 using threaded studs 228 (only 2 of which are shown) whichare welded to base 212. A cable stub 230 is inserted through into base212 using a fitting 232 designed to provide both strain relief for thecable stub and sealing of this entry. Not shown are additional fittings,such as pressurization, venting and telecommunications accessories thatpierce the bottom surface of base 212. These additional fittings areeach designed with features to seal their entry points into the base212. For additional sealing integrity, the bottom of the base and thevarious fittings that pierce the base are covered with a semi-rigidencapsulant 234.

[0079] A plurality of thermal sleeves 170 are positioned inside dome 214to form a cylindrical thermal core that is in complementary thermalcontact with the inner surface of dome 214. Because HDSL repeaters havea high thermal density that is distributed throughout the module, the4-surface collection provided by the sleeve is desirable. Furthermore,by moving the sleeve to the periphery of the thermal core, the transfermember can be reduced to the thickness of the sleeve, virtually shortingout the thermal resistance to the enclosure. Based upon the amount ofwaste heat generated by the HDSL repeaters, the maximum specifiedambient temperature, the amount of waste heat that can be transferred tothe ambient air through the top of the dome and the base and assuming abelow ground environment, each sleeve's distribution member 176 wasrequired to be approximately 10 inches high and occupy approximately 45degrees of the circumference of the dome to provide a large enoughthermal interface to accommodate 8 HDSL repeater modules.

[0080] In order to service the repeater housing, a lineman must be ableto remove dome 214. However, to maximize thermal transfer to the ambientair the sleeve's distribution members should be held in close if notintimate thermal contact with the dome. To this end, an actuatormechanism 236 urges the sleeves against the dome's sidewalls when it issealed to the base and retracts the sleeves to allow the dome to beremoved. From the thermal transfer standpoint, alternatives consideredincluded 1) spacing the sleeves away from the dome at a distancesufficient to accommodate manufacturing tolerances and allow easyinstallation and removal of the dome or 2) spring loading the sleevesagainst the inside of the dome surface with a force light enough toallow the cover dome to be conveniently installed and removed. One ofthe environmental conditions for which repeater housings must bedesigned is what the telecommunications industry refers to as a Zone 4earthquake. Mere spring loading probably would not provide enoughsupport to protect the electronics inside the dome.

[0081] In order for actuator mechanism 236 to move sleeves 170 radially,each sleeve is secured to a platform 238 with four shoulder screws 240positioned in slots 242 so as to guide but restrain sleeves 170. Sincerepeater modules 108 must move with the sleeves, repeater connectors 244must be free to move in concert with the sleeves. Therefore, asillustrated in FIGS. 12 and 13, a connector clip 246 is secured torepeater connector 244. The clip's ears 248 spring outward about 10degrees and fit into alcoves 250 formed into the sleeves therebyaligning each repeater connector with its host sleeve and forcing eachrepeater connector to move radially in concert with its host sleeve. Torestrain repeater connectors 244 in the vertical direction, they arepositioned in cut-outs 252 in platform 238 while mounting connector ears254 on the connector rest on the platform and stops 256 on the connectorclip slide under the platform. A standard SPC voltage surge protectorassembly 258 is plugged on to the connector's wire wrap pins 260 andcan, therefore, move with the sleeve. Repeater retainer 262 is used tosecure a repeater module once plugged into a sleeve assembly.

[0082] Platform 238 and an assortment of sleeve positions areillustrated in FIG. 14. Starting at 12 o'clock and working in acounterclockwise direction as indicated on mast cap 241, position number1 shows the shoulder screw slots 242 and repeater connector cut-out 252in platform 238. Position 2 shows an installed 239 mini-repeater, whichis held in position with guides 262 mounted in guide slots 264 formed inthe sleeve's extruded wall. Positions 3 and 7 show sleeves and theirrepeater connectors. Positions 4, 6 and 8 are shown with 239 Double Widerepeater modules installed. Position 5 shows a sleeve with neitherrepeater connector nor repeater installed. The sleeves in positions 2,3and 4 are shown expanded against dome 214. The sleeves in positions 6, 7and 8 are shown in the fully retracted position, a travel distance ofapproximately 0.1 inches.

[0083] To move the sleeves radially and exert the pressure necessary tohold them against the inside surface of the cover dome in the presenceof worst case earthquake forces, actuator mechanism 236 includes amodified parallelogram spring 266 that translates the vertical motion ofa mast assembly 267 into radial force for retraction and expansion ofthe sleeves. Each parallelogram spring 266 slides into complementaryT-slots 268 a and 268 b (shown best on FIG. 10) formed in each sleeveand on the eight faces of mast hub 270. Once installed, theparallelogram spring is retained in position on the glove by a Hammlatch 272 and on the mast hub by a bottom mast cap 274 and a top mastcap 276.

[0084] As shown best on FIG. 15, a mast shaft 278 passes through masthub 270 and through a hole in platform 238. The upward travel of themast shaft is limited by an E-clip 280. The upward travel of the masthub with respect to the mast shaft is limited by an assembly of thrustbearings 282 and another E-clip, thus allowing the mast shaft to rotatewithin the mast hub. Mast hub 270 is urged upward by a spring 284, whichhas sufficient strength to retract all eight gloves against the worstcase combination of tolerances, wear and friction expected over therepeater housing's operating life.

[0085] In order to expand the sleeves, top drive screw 286 is screweddown into its mating top drive seat 288. As the top drive screw movesdownward, the attached alignment cone 290 engages the top of mast shaft278 (the length of which can be adjusted in manufacturing to offsettolerance buildup). As the top drive screw continues downward, thrustbearings 282 allow mast shaft 278, which is now in frictional contactthrough the alignment cone 290 with top drive screw 286, to freelyrotate within mast hub 270. The downward motion of the top drive screwnow forces the mast shaft and mast hub downward until the top drivescrew reaches the end of its travel against the top drive seat. The topdrive assembly contains o-ring seals and sealing surfaces sufficient toprevent leakage into or from the environmental enclosure once the topdrive screw is seated against the top drive seat.

[0086] As top drive screw 286 forces mast shaft 278 and mast hub 270downward, toward platform 238, the portion of each parallelogram spring266 fastened to the mast hub must also move toward the platform. Sincethe other side of the parallelogram spring is fastened to sleeve 170 andthe sleeve is fastened to the platform, the only degree of freedomallowed the parallelogram spring is to force the sleeve radiallyoutward, away from the mast. As illustrated in FIG. 15a and 15 b, whichrespectively show the actuator mechanism in its expanded and retractedpositions, the arms of the parallelogram spring not fastened to the masthub or sleeve are designed to flex in order to accommodate the range ofmotion needed from the mast hub to provide for adequate expansion andretraction forces over the full range manufacturing tolerances.

[0087] In addition to the thermal transfer through the sleeve'sdistribution member to the sidewalls, FIGS. 15a and 15 b also illustrateanother important waste heat transfer and distribution path. Sleeves 170rest upon platform 238 and, therefore, although this is a poor qualitythermal joint, can transfer some heat to the platform, which ismanufactured from aluminum thicker than required for its structuralpurpose. Thick aluminum bars called downrights 292 are welded to theplatform to form a good thermal joint, which are, in turn, attached toan aluminum frame called uprights 294 at two pivot points 296 usingoverlapping thermal joints 298. The pivot points allow the thermallyenhanced chassis, which is everything attached to the platform, to tiltas illustrated in FIG. 16 for access to the underside of the platformand, in particular, to the voltage surge protector modules 258.

[0088] The upright bracket is bent to form a large foot 300 that issecured to base 212 with welded studs 302. Although the base is thinstainless steel of poor thermal conductivity, this design creates anoverlapping thermal joint by placing the feet of the upright brackets inclose proximity with flanges 304 by which the repeater housing mountingbracket 226 is secured to the repeater housing base. This is not aprimary thermal transfer and distribution path, however, the effort andcost required to create it are relatively small and the heat removed viathis path can reduce the temperature of the rest of the repeater housingand the installed repeaters several degrees centigrade.

[0089] Similarly, although natural convection within the repeaterhousing is no longer the primary heat transfer method, it is prudent tocontinue to utilize all available thermal transfer paths. Therefore, asshown most clearly in FIG. 14, numerous air holes 306 are placed in theplatform to facilitate the circulation of air from the base to the topof the cover dome and small corrugations 308 are formed on the outersurfaces of the sleeves to slightly increase the surface area andsubstantially increase the radiation emissivity.

[0090] In addition to the waste heat generated within the repeaterhousings, solar loading, i.e., the heat absorbed from solar energyincident upon above ground repeater housings, can be a serious problem.The SPC 7000 Series enclosure may intercept up to 150 watts of incidentenergy. With an appropriate white coating and allowing for aging andnormal surface contamination, it is practical to attain 70% reflectancefrom a smooth surface repeater housing. However, up to 45 watts of solarenergy may be absorbed, which is equivalent to over 7 HDSL repeaters.

[0091] One solution is to expand the surface area of the repeaterhousing a sufficient amount to transfer the additional solar energy tothe surrounding ambient air. If the expanded area is achieved with finsor convolutions of the surface, the area can be increased substantiallywith a minimal increase in the projected area of the housing thatcaptures the solar energy. Unfortunately, this prospective solution isalso limited in that such fins or convolutions also significantly reducethe surface reflectivity. This occurs because such fins and convolutionscause multiple reflections and, thereby, become light traps. Fins orconvolutions sized to double the effective surface area of a repeaterhousing would also reduce the reflectivity of a 70% reflective surfaceto 40% or less on the expanded surface area. This problem is overcome byplacing a reflective solar shield around the expanded surface area.

[0092] The solar shield assembly 350 illustrated in FIG. 17 includesstainless steel fins 352 that are spot welded to the sidewalls of dome214 and a thin stainless steel cylinder 354 is spot welded to fins 352to form an annular ring spaced about 1.25 inches from dome 214, with theentire assembly then painted with an appropriate white coating. A debrisskirt 356 is fastened to the environmental enclosure above seam 358 withbase 212 to prevent debris from being caught on the edge of V-grooveclamp 224.

[0093] Solar shield assembly 350 functions as follows: when the sunangle is high overhead, little solar energy is incident upon thevertical sides of the repeater housing. The smooth white cover reflectsa large fraction of the incident solar energy and the inner portions ofthe fins closest to the environmental enclosure increase the externalsurface area sufficiently to dissipate the extra solar energy to thesurrounding ambient air. Although thin stainless steel fins are poorthermal conductors, as previously explained and illustrated as FIG. 8e,short fins can be useful.

[0094] As the sun angle shifts from the vertical towards the horizontal,the solar shield 354 intercepts most of the solar energy that wouldotherwise heat the vertical side of the environmental enclosure dome214. This, of course, heats the solar shield. However, the shield hasboth its inner and outer surfaces available to transfer the solar energyinto the surrounding ambient air via natural convection. Furthermore,the outer portions of fins 352 also serve as an expanded externalsurface to aid in the natural convection transfer. This combination ofsurfaces is more than enough to dissipate to the ambient air the solarenergy absorbed by solar shield 354 and that portion of the fins 352exposed to the solar radiation.

[0095] In some applications, it is desirable for the environmentalenclosure to operate at a temperature lower than that of the solarshield. In such cases, it is important to minimize the heat conductedfrom the solar shield 354 through fins 352 to environmental enclosure214. FIG. 18a illustrates a portion of fin 352 having an inside tab thatis fastened to the environmental enclosure and an outside tab that isfastened to the solar shield. If manufactured from a material of onlymoderate thermal conductivity such as stainless steel, the inner andouter portions of the fin near the environmental enclosure and the solarshield, respectively, will serve as an extra surface from which todissipate heat into the natural convective air flow. However, ifdesigned correctly, the fin will not be effective at conductingsignificant amounts of heat the full width of the fin from a hottersolar shield to a cooler enclosure as heat is removed from the surfacesof the fin via natural convection.

[0096]FIGS. 18b and 18 c illustrate ways to use parts of fin 352 asnatural convection surfaces while increasing thermal isolation betweenthe environmental enclosure and solar shield 354. In FIG. 18b, slots 360have been cut in the fin to reduce the cross sectional area availablefor thermal conduction while leaving enough material to maintainmechanical integrity. In FIG. 18c, in addition to the slots, theconductive distance has been increased by adding a series of bends 362to the portion of the fin providing the mechanical connection.

[0097] Although the modified SPC 7000 Series repeater housingillustrated in FIGS. 12-16 incorporating the solid thermal conductioncollection, transfer and distribution principles represents asubstantial improvement in thermal transfer capability over the knownSPC 7000 Series, it still suffers from the access difficultiesassociated with “tilt, swivel and around the back” and requires amoderately complex mechanism to expand and retract the thermal sleeves,accommodate an accumulation of manufacturing tolerances, wear and tear,survive a zone 4 earthquake and protect its housed repeaters from ashotgun blast at close range. These limitations are overcome byincorporating the thermal transfer techniques described in FIGS. 8a-8 e,9 and 10 with the voltage protector assemblies described in FIGS. 11a-11d that facilitate direct top or front access.

[0098] Although applicable to any housing shape or configuration, thetechnique is illustrated in the context of two different cylindricalrepeater housings. The first, illustrated in FIGS. 19 and 20, isdesigned for use above-ground in a vertical orientation. The second,illustrated in FIGS. 21-24, is designed for use below-ground in ahorizontal orientation. The intended orientation is important because itdictates the orientation of the external fins to optimize naturalconvective air flow.

[0099] As shown in FIGS. 19 and 20, an above-ground cylindrical repeaterhousing 400 comprises a cylindrical base 402 that receives a cable stub404 that is preferably terminated with a master connector 406. Amounting bracket 408 is used to mount the base 402 in an uprightposition on a telephone pole, for example. A plurality of repeaterconnectors 410 are disposed radially around a PCB 412 with theirprotector connectors 414 positioned towards the center of the PCB. Amating master connector 416 is positioned at the center of the PCB forconnection to master connector 406. Alternately, any of the protectorassemblies illustrated in FIGS. 11a-11 d could be used and theconnectors could be wired using conventional wire-wrapping techniquesinstead of the master connector. Furthermore, if on-site access to thewiring is not required, the base can be eliminated and the cable andconnections below the PCB encapsulated to provide the necessarymechanical strength and environmental protection at a considerable costsavings.

[0100] A thermal chassis 418 is placed over PCB 412 to define a radialslot 420 over each repeater connector 410 and provides the collection,transfer and distribution functions as described in detail previously,and, preferably, to define an inner slot 422 over each protectorconnector 414. Repeater modules 424 and protectors 426 are inserted inslots 420 and 422, respectively, and mounted in connectors 410 and 414.The outer surface of thermal chassis 418 is preferably formed with anaxial extrusion pattern 428 such as the bifurcated fins 430.

[0101] A thin-walled shell 432, manufactured from a material suitablefor environmental protection such as stainless steel, plastic orfiberglass, fits in complementary thermal contact around thermal chassis418. Shell 432 is preferably corrugated to define a plurality of axialfins 434 that fit over the chassis' extrusion pattern 428. Alternately,shell 432 and chassis 420 could utilize any of the other expandedexternal surface designs illustrated in FIGS. 8a-8 e or even a smoothsided, non-expanded design.

[0102] Flanges 436 and 438 are formed at both ends of shell 432 forconnection to base 402 and an access cover 440, respectively, usingV-groove clamps and seals (not shown). The seam at flange 436 providesbottom access to the wiring on the underside of thermal chassis 420.This is useful during manufacturing and on very rare occasions in thefield. The seam at flange 438 provides direct top access to thermalchassis 420 for removing repeater modules 424 and voltage surgeprotectors 426.

[0103] Thermal chassis 420 and thin-walled shell 432 can be manufacturedin many different ways depending upon the requirements of a specificrepeater housing such as thermal transfer capacity, quantity and type ofrepeaters and cost. One approach is to use a thermally conductiveadhesive to glue together a plurality of thermal sleeves 442, similar tothe one shown in FIG. 10 but extended to cover the protector connectorand rotated ninety degrees to optimize the available space. Extrusionpattern 428 can be either formed into the distribution surface of thesleeve or separately fastened thereto. Alternately, the entire thermalchassis 420 can be cast or molded as a single unit or molded inside theshell 432. In addition, individual thermal sleeves could be fit insidethe shell and mechanically secured so that they could be disassembled ata later time.

[0104] Shell 432 can be a separate piece, formed, cast or molded withthe desired complementary extrusion pattern, that is slid over thethermal chassis to provide a compression fit. The compression fit can beimproved by forming the chassis and shell with a complementary taper asshown in FIG. 19 that forces the chassis' extrusion pattern into theshell to provide a good thermal and mechanical joint. Alternately, theshell can be molded over the chassis using a moldable material such asplastic. This approach avoids the need for a tapered design andaccommodates the manufacturing tolerances of the chassis in the wallthickness of the shell.

[0105] Because repeater housing 400 is intended for use above ground, itshould also accommodate solar loading. One approach is to place a solarshield of the type illustrated in FIG. 18 around the housing. Inaddition, thermal transfer from access cover 440 to the chassis shouldbe minimized. This is accomplished by making the joint between the coverand chassis a poor thermal conductor and possibly insulating the insideof the access cover. In contrast, thermal transfer from the chassis tothe relatively cool base 402 and to mounting bracket 408 should beencouraged. This is accomplished using a combination of overlapping andinterdigitated thermal joints not illustrated for this embodiment, butusing the techniques described for the front access cover in thehorizontal cylinder ahead. In addition, thermal sleeves 442 andparticularly the portion that defines the inner slot for the protectorsare designed to form overlapping thermal joints 444 that form across-conduction path around the interior of the chassis. As a result,heat from a sunny side of the housing can be transferred to the shadyside through the cross-conduction path.

[0106] As shown in FIGS. 21 through 23, below-ground cylindricalrepeater housing 500 is similar to the above ground version except thata) the fin structure is formed circumferentially around the enclosure,rather than axially, to conform to the fact that hot air rises and thatb) solar loading is not a concern. As shown, the thermal chassis'extrusion pattern includes a plurality of circumferential corrugations,or fins, 502 that match the shell's circumferential corrugations 504.With a circumferential fin/corrugation pattern, the shell cannot beslipped over the thermal chassis. While it is possible to insertindividual thermal sleeves into the shell, some volume and distributionefficiency would be lost. More appealing are the two alternatives ofeither molding the shell over the chassis or molding the chassis insidethe shell. As shown, the shell 506 can be molded over chassis 508.

[0107] For this horizontal embodiment, an additional manufacturingalternative is illustrated in FIG. 24, in which the circumferentialcorrugations 504 are inclined from the axis of the cylinder to formthreads and the fins 502 on the chassis are similarly inclined. Withthese matched threads, a chassis and an outer shell can be mated byscrewing them together. If the chassis and shell are also tapered, thethreaded and tapered components can be assembled in a manner and withthe benefits discussed for the tapered vertical cylinder embodiment.

[0108] The absence of solar loading underground provides an opportunityto use expanded surfaces on both ends of the repeater housing. Asillustrated in FIG. 21, a thermal interface member 520, formed from asuitable thermally conductive material such as aluminum or thermallyconductive plastic, transfers waste heat from the chassis to the frontaccess cover 522. The exterior of interface member 520 has fins 524 thatfit within corrugations 526 formed in access cover 522. The interiorsurface of interface member 520, illustrated in plan view in FIG. 22b,has formed on it triangularly shaped thermal conductors 528 that fitwithin mating triangular slots 530, illustrated in FIG. 22a, in thethermal chassis and implements twelve sets of overlapping thermal jointsto transfer waste heat from the chassis to the access cover. Similarly,a twelve faced ring 523 is formed about the center of interface member520 to form an additional thermal interface joint with the interiortwelve sided surface formed by the juncture 534 of the individualthermal sleeves that combine to form the chassis.

[0109] The side profile of these overlapping thermal joints isillustrated in FIG. 23a where the access cover is removed in FIG. 23bwhere the access cover is in place. For purposes of clarity, the base isshown in a side, rather than a sectional view, but would incorporate asimilar interface structure for transferring heat to the mountingbracket. Although this interface member is used in this embodiment totransfer heat to the front access cover, similar interface members,utilizing overlapping and/or interdigitated thermal transfer joints, canbe used to move heat to other regions within and without repeaterhousings, certainly including to the repeater housing base asanticipated in the preceding discussion of the vertical cylinderembodiment.

[0110] While several illustrative embodiments of the invention have beenshown and described, numerous variations and alternate embodiments willoccur to those skilled in the art. For example, although the inventionwas discussed in the context of the cylindrical SPC 7000 type enclosure,the principles are equally applicable to other housing shapes,rectangular, for example. Although repeater housings for 8 and 12 239mini and double wide repeaters have been illustrated, the invention canbe applied to repeater housings intended for greater and smallerrepeater quantities and for other repeater types such as the type 400.Although the direct access voltage surge protector design has been shownin association with the thermal elements of the invention, such directaccess protector designs are expected to find application in repeaterhousings where thermal enhancement is not required, but improved accesscould be of value. Such variations and alternate embodiments arecontemplated, and can be made without departing from the spirit andscope of the invention as defined in the appended claims.

I claim:
 1. A passively cooled repeater housing for use in atelecommunication network's wire transmission local loop outside plantto house a plurality of standardized repeater modules, comprising: athermal chassis for mounting a plurality of repeater modules thatgenerate waste heat, said chassis comprising for each said repeatermodule: a thermal collection member that forms a first thermal interfacewith said repeater module to collect its waste heat; a thermal transfermember that transfers the collected waste heat along a conduction pathaway from said repeater module; and a thermal distribution member thatdistributes the waste heat over an enlarged surface area, and anenvironmental enclosure around said chassis that provides mechanical andenvironmental protection for said repeater modules and said thermalchassis, said enclosure having a base, sidewalls disposed in closeopposition to the thermal distribution members to form a second thermalinterface for transferring the waste heat between the distributionmember and the environmental enclosure and then convectivelytransferring the waste heat to the ambient air, and a removable coverfor gaining access to said repeater modules to interchange them onsite.2. The repeater housing of claim 1, wherein said environmentalenclosure's cover extends the length of said repeater modules and issealed to a base, said thermal distribution member being positionedinside said environmental enclosure and mechanically separable from saidcover so that said cover can be removed by breaking the seal to saidbase.
 3. The repeater housing of claim 2, wherein said chassis furthercomprises an actuator mechanism that urges the thermal distributionmembers against the sidewalls of said cover when it is sealed to thebase and retracts said thermal distribution member to allow said coverto be removed.
 4. The repeater housing of claim 3, wherein saidenvironmental enclosure is cylindrical, said chassis comprising: aplurality of repeater connectors slidably disposed in a circle insidethe enclosure towards the base for mounting and electrically connectingthe repeater modules to the local loop; and a plurality of thermalsleeves that are slidably mounted over the respective repeaterconnectors to mechanically support said repeater modules, each saidthermal sleeve having an interior dimension that forms said firstthermal interface with said repeater module for collecting waste heatand a front arcuate surface that transfers the collected waste heat toand distributes the waste heat over the cylindrical sidewalls, saidactuator mechanism sliding said thermal sleeve, connectors and repeatermodules radially outwards against the cylindrical sidewalls when saidcover is sealed and retracting them to allow said cover to be removed.5. The repeater housing of claim 1, wherein said environmental enclosurefurther comprises a fixed base and a shell mounted between said base andsaid cover, said thermal distribution members being mechanically fixedto said shell to improve the thermal transfer of the second thermalinterface.
 6. The repeater housing of claim 5, wherein said chassis'thermal distribution members are compression fit inside said shell. 7.The repeater housing of claim 6, wherein said shell is corrugated todefine axial fins that increase the surface area of said second thermalinterface and said thermal distribution members having extrusions thatfit inside said axial fins to improve the distribution of said wasteheat over that enlarged surface area.
 8. The repeater housing of claim7, wherein each said distribution member comprises at least onebifurcated fin that is pinched inside an axial fin.
 9. The repeaterhousing of claim 7, wherein said distribution members comprise acomplementary corrugation that forms a laminate structure with saidshell.
 10. The repeater housing of claim 7, wherein said shell andthermal distribution members have a complementary taper that improvestheir compression fit.
 11. The repeater housing of claim 7, wherein saidshell is molded over the extruded distribution members to define saidaxial fins.
 12. The repeater housing of claim 7, wherein said shell iscylindrical and said thermal distribution members are bonded together toform a cylinder, said shell and distribution members havingcomplementary circumferential fins.
 13. The repeater housing of claim12, wherein said shell is molded over said distribution members.
 14. Therepeater housing of claim 5, wherein said chassis further comprises aplurality of repeater and protector connector pairs that are positionedtowards the base and away from the removable cover for mounting andelectrically connecting the repeater modules and a plurality of voltagesurge protectors, respectively.
 15. The repeater housing of claim 14,wherein said repeater and protector connectors are female printedcircuit board (PCB) edge connectors that are positioned side-by-sidewith the repeater connector elevated above the protector connector sothat the voltage surge protector is mounted underneath the repeatermodule.
 16. The repeater housing of claim 14, wherein said Protectorconnector is spaced apart from said repeater connector so that saidvoltage surge protector can be removed and replaced on-site withouthaving to remove said repeater module.
 17. The repeater housing of claim16, wherein said voltage surge protector extends along the length ofsaid repeater module to simplify access through the opening in saidshell.
 18. The repeater housing of claim 5, wherein the exterior surfaceof said enclosure is subjected to unbalanced solar loading in theambient air, further comprising thermal cross-transfer members thattransfer heat from one repeater module to the thermal distributionmember of another repeater module.
 19. The repeater housing of claim 5,further comprising thermally conductive external and internal mountingbrackets for mounting said environmental enclosure, said internalmounting bracket transferring some of the collected waste heat throughthe base to the external mounting bracket.
 20. The repeater housing ofclaim 19, wherein said internal and external mounting brackets form anoverlapping thermal joint to enhance heat transfer.
 21. The repeaterhousing of claim 19, wherein said internal and external mountingbrackets form an interdigitated thermal joint to enhance heat transfer.22. The repeater housing of claim 5, wherein said cover comprises aplurality of thermal transfer members that, when sealed, provide aplurality of conduction paths from said repeater modules to said cover.23. The repeater housing of claim 22, wherein said cover's thermaltransfer members form an overlapping thermal joint with the thermalcollection members to provide said conduction paths.
 24. The repeaterhousing of claim 1, wherein the shape of said thermal distributionmember is complementary with the shape of the interior surface of saidsidewalls with the total surface area of all said distribution membersbeing greater than that of said cover.
 25. The repeater housing of claim1, wherein the thermal distribution member comprises a fin that isaffixed to the outer surface of said enclosure immediately opposite saidthermal transfer member so that said waste heat passes through saidsecond thermal interface to said fin where it is convectivelytransferred to the ambient air.
 26. The repeater housing of claim 1,wherein the exterior surface of said enclosure is subjected tounbalanced solar loading in the ambient air, further comprising aplurality of fins disposed around the exterior of said enclosure thatextend outward to increase the total surface area that transfers wasteheat to the ambient environment and a shroud around the fins thatprevents sun light from being trapped in the fins and overheating therepeater housing.
 27. The repeater housing of claim 26, wherein saidfins have slits that form a thermal barrier that blocks the sun'sthermal energy from penetrating to and heating the enclosure.
 28. Therepeater housing of claim 27, wherein said fins are bent at said slitsto increase the thermal barrier and provides a degree of shockabsorption.
 29. A passively cooled repeater housing for use in atelecommunication network's wire transmission local loop outside plantto house a plurality of standardized repeater modules, comprising: athermal chassis having a plurality of repeater connectors for mounting arespective plurality of repeater modules that generate waste heat and aplurality of having protector connectors for mounting a respectiveplurality of voltage surge protectors, each said protector connectorbeing spaced apart from its paired repeater connector; and anenvironmental enclosure around and fixed to said chassis for providingmechanical and environmental protection for said repeater modules, saidenclosure having an I/O port for wiring the connectors to the local loopand a field accessible cover for providing top access to said chassis toreplace said voltage surge protectors on-site without having to removesaid repeater modules, said environmental enclosure removing a smallportion of the waste heat from the repeater modules via convection tothe cover and then to the ambient air, said thermal chassis collecting amajority of the repeater modules' waste heat through respective thermalinterfaces, transferring the waste heat along respective conductionpaths to the sidewalls of the environmental enclosure, and distributingthe waste heat over a surface area larger than that of the cover to forma second thermal interface for transferring waste heat between thethermal chassis and the enclosure and then convectively transferring thewaste heat to the ambient air.
 30. The repeater housing of claim 29,wherein said enclosure is corrugated to define axial fins that increasethe surface area of said second thermal interface and said thermalchassis having extrusions that fit inside said axial fins to improve thedistribution of said waste heat over that enlarged surface area.
 31. Therepeater housing of claim 30, wherein each said thermal chassiscomprises a plurality of bifurcated fins that are pinched insiderespective axial fins.
 32. The repeater housing of claim 30, whereinsaid thermal chassis has a complementary corrugation that forms alaminate structure with said enclosure.
 33. The repeater housing ofclaim 30, wherein said enclosure is molded over the extruded thermalchassis to define said axial fins.
 34. The repeater housing of claim 29,wherein said voltage surge protector extends along the length of saidrepeater module to simplify the top access.
 35. The repeater housing ofclaim 29, wherein the exterior surface of said enclosure is subjected tounbalanced solar loading in the ambient air, further comprising thermalcross-transfer members that transfer heat from the relatively hot sideof the enclosure to the relative cool side.
 36. A passively cooledrepeater housing for use in a telecommunication network's wiretransmission local loop outside plant to house a plurality ofstandardized repeater comprising: an environmental enclosure having afixed base an I/O port for receiving degraded signals from the localloop and returning regenerated signals to the local loop, a shell onsaid base having sidewalls that define an inner volume, and a removablecover on said shell for gaining access to said inner volume; and athermal chassis mounted in said fixed base comprising: a plurality ofrepeater connectors disposed around the perimeter of the inner volumetowards the base for mounting a respective plurality of repeater modulesin said inner volume; and a plurality of thermal sleeves that aremounted over the respective repeater connectors to mechanically supportsaid repeater modules, each said thermal sleeve having an interiordimension that forms a first thermal interface with said repeater modulefor collecting waste heat and a front surface that transfers thecollected waste heat to an interior surface of the shell's sidewalls anddistributes the waste heat to form a thermal interface with said shellfor transferring heat through the shell and to the ambient air.
 37. Therepeater housing of claim 36, wherein said environmental enclosure'scover is cylindrical and extends the length of said repeater modules toa base, said thermal chassis further comprising an actuator mechanismthat urges the thermal sleeves radially outwards against the sidewallsof said cover when it is sealed to the base and which is capable ofretracting said sleeves to allow said cover to be removed.
 38. Therepeater housing of claim 36, wherein said enclosure comprises athin-walled stainless steel dome.
 39. The repeater housing of claim 35,wherein said environmental enclosure comprises a cylindrical shellmounted on a fixed base, said shell having an extrusion pattern thatincreases the enclosure's surface area, said thermal chassis having acomplementary extrusion pattern that improves the distribution of thewaste heat over the enlarged surface area.
 40. The repeater housing ofclaim 39, wherein said cylindrical shell and the thermal chassis have acomplementary taper that provides a compression fit.
 41. The repeaterhousing of claim 40, wherein said shell is corrugated to form itsextrusion pattern and said thermal sleeves each comprise at least onepair of closely spaced fins that are pinched inside the corrugations.42. The repeater housing of claim 40, wherein said shell is corrugatedto form its extrusion pattern and said thermal chassis has acomplementary corrugation that forms a laminate structure with saidenclosure.
 43. The repeater housing of claim 39, wherein said shell ismolded over the thermal chassis to define its extrusion pattern.
 44. Therepeater housing of claim 39, wherein said shell has a plurality ofcircumferential fins and said thermal chassis has a complementaryplurality of circumferential fins.
 45. The repeater housing of claim 44,wherein said shell is molded over the thermal chassis to define thecircumferential fins.
 46. A passively cooled repeater housing for use ina telecommunication network's wire transmission local loop outside plantto house a plurality of standardized repeater modules, comprising: acylindrical base having a port for receiving wires from the local loop;a cylindrical dome on said base having an integrally formed shell thatfits over said base and a cover having a hole formed at its center; amechanism for sealing said dome to said base; and a thermal chassiscomprising: a circular platform in said base, said platform having aplurality of slots that are regularly spaced around the platformadjacent the shell; a plurality of repeater connectors that are free toslide in the respective slots in different radial directions whileconnected to said wires; a plurality of thermal sleeves mounted on saidplatform over the respective repeater connectors that are also free toslide in said slots in said radial directions, each said thermal sleevehaving an interior dimension that forms a first thermal interface with arepeater module mounted in said connector for collecting waste heat anda front arcuate surface that first transfers and then distributes thewaste heat over the shell thereby forming a second thermal interface fortransferring heat through the shell and to the ambient air; an internalmounting bracket in said base that allows said platform to tip when thedome is removed to access the connector wiring; and an actuatormechanism that extends axially from the center of the platform throughthe hole in said cover and radially to the respective thermal sleeves, adownward axial force on said mechanism producing outward radial forceson said thermal sleeves that urge their arcuate surfaces against theshell, the release of said axial force causing said thermal sleeves toretract so that said dome can be removed.
 47. The repeater housing ofclaim 46, wherein the total surface area of all said arcuate surfaces isgreater than the surface area of said cover.
 48. The repeater housing ofclaim 47, wherein said thermal sleeves are in thermal contact with saidplatform, further comprising a thermally conductive external mountingbracket for mounting said environmental enclosure, said internalmounting bracket transferring some of the collected waste heat to theexternal mounting bracket.
 49. The repeater housing of claim 48, whereinsaid internal and external mounting brackets form an overlapping thermaljoint to enhance heat transfer.
 50. The repeater housing of claim 43,wherein the exterior surface of said dome is subjected to unbalancedsolar loading in the ambient air, further comprising a plurality of finsdisposed around the exterior of said dome that extend outward toincrease the total surface area for transferring waste heat to theambient environment and a shroud around the fins that prevents sun lightfrom being trapped in the fins and overheating the repeater housing. 51.The repeater housing of claim 50, wherein said fins have slits that forma thermal barrier that blocks the sun's thermal energy from penetratingto and heating the dome.
 52. The repeater housing of claim 46, whereinsaid actuator mechanism comprises: a mast that extends axially from thecenter of the platform towards the hold in said cover; a mast springaround said mast on said platform; a movable hub around said mast onsaid mast spring; a plurality of spring arms that are positionedradially about said movable hub and are connected to respective thermalsleeves; and a top drive screw assembly that extends through the hole insaid cover to just above the end of said mast; the rotation of the topdrive screw assembly in one direction producing a downward axial forceon the end of the mast urging the movable hub downward and the springarms radially outward, the rotation of the external compression nut inthe opposite direction relieving the axial force allowing the thermalsleeves to retract.
 53. A passively cooled repeater housing for use in atelecommunication network's wire transmission local loop outside plantto house a plurality of standardized repeater modules, comprising: acylindrical base having an I/O port for bringing wires from the localloop inside said housing; a plurality of connectors in said base formounting repeater modules and electrically connecting them to saidwires; a thermal chassis having a plurality of thermal sleevespositioned over the respective connectors for supporting said repeatermodules and collecting their waste heat and having an extrusion patternaround said sleeves that distributes the waste heat over an enlargedsurface area; a cylindrical shell on said base, said shell having acomplementary extrusion pattern in close thermal contact with saidchassis' extrusion pattern to increase the external surface area forconvectively transferring waste heat to the ambient air; and acylindrical cover on said shell, said cylindrical base, shell and covertogether providing mechanical and environmental protection for saidrepeater modules and said thermal chassis, said cylindrical cover beingremovable to provide top access to said repeater modules to remove themon-site.
 54. The repeater housing of claim 53, wherein said cylindricalshell and the chassis have a complementary taper that provides acompression fit.
 55. The repeater housing of claim 54, wherein saidshell is axially corrugated to form its extrusion pattern and saidthermal sleeves each comprise at least one pair of closely spaced axialfins that are pinched inside the corrugations.
 56. The repeater housingof claim 53, wherein said cylindrical shell is molded over said chassis.57. The repeater housing of claim 53, wherein said thermal sleeves arein thermal contact to form a thermally conductive path around thethermal chassis to cross transfer waste heat from a relatively hot areato a relatively cool area to improve overall transfer to the ambientair.
 58. The repeater housing of claim 57, wherein each said thermalsleeve has an interior dimension that forms a first thermal interfacewith said repeater module for collecting waste heat and an arcuate frontsurface that first transfers and then distributes the collected wasteheat over the complementary extrusion pattern.
 59. The repeater housingof claim 58, further comprising a plurality of protector connectorspositioned radially inward from the respective repeater connectors formounting voltage surge protectors which can be replaced without havingto remove said repeater modules.
 60. The repeater housing of claim 59,wherein said thermal sleeves extend around said protector connectors toimprove the conduction path for cross transferring waste heat.
 61. Therepeater housing of claim 53, further comprising: a thermally conductiveplatform for supporting the thermal chassis; and a thermally conductivebracket that connects said platform to said base thereby transferring aportion of the total waste heat through said base to the ambient air.62. A passively cooled repeater housing for use in a telecommunicationnetwork's wire transmission local loop outside plant to house aplurality of standardized repeater modules, comprising: a cylindricalbase having an I/O port for bringing wires from the local loop insidesaid housing to receive degraded transmission signals and returnregenerated transmission signals; a plurality of connectors in said basefor mounting repeater modules and electrically connecting them to saidwires; a cylindrical shell on said base, said shell having a pluralityof circumferential fins that increase its surface area; a cylindricalthermal chassis having a plurality of thermal sleeves over therespective connectors for supporting said repeater modules andcollecting their waste heat and having a complementary plurality ofcircumferential fins that fit inside the cylindrical shell to distributethe waste heat over the cylindrical shell for convective transfer to theambient air; and a cylindrical cover on said shell, said cylindricalbase, shell and cover providing mechanical and environmental protectionfor said repeater modules and said thermal chassis, said cylindricalcover being removable to provide top access to said repeater modules toremove them on-site.
 63. The repeater housing of claim 62, wherein saidcylindrical shell is molded over the cylindrical thermal chassis. 64.The repeater housing of claim 62, wherein said thermal sleeves are inthermal contact to form a thermally conductive path around the thermalchassis to cross transfer waste heat from a relatively hot area to arelatively cool area to improve overall transfer to the ambient air. 65.The repeater housing of claim 59, further comprising an interface memberthat fits over the thermal chassis to provide a plurality of conductionpaths from said thermal chassis to said cover.
 66. The repeater housingof claim 65, wherein said interface member forms overlapping thermaljoints with the thermal sleeves to provide said conduction paths.